键盘输入一个高精度的正整数s（<=240位），去掉任意k个数字后剩下的数字按原左右次序将组成一个新的正整数。编程对给定的s和k，寻找一种方案，使得剩下的数最小。

输入：

s

k

输出：

最后剩下的最小数

｛样例输入}

178543

4

｛样例输入}

13-Keyboard input of a high-precision positive integer s (< = 240 bit), remove any remaining k-digit number after the original order will be formed around a new positive integer. Programming on a given s and k, find a program that remaining was the smallest. Input: s k output: The last remaining minimum number of sample input () 1785434 (13) Sample input